1. Field of the Invention
The present invention relates in general to semiconductor packages and to an improvement in structures of the packages for connecting a plurality of pads of a semiconductor chip to their inner leads of a lead frame but directly connecting a chip pad of the lead frame to the inner leads through a soldering, thereby achieving the recent trend of diminution and thinness of the packages.
2. Description of the Prior Art
With reference to FIG. 1, there is shown a typical semiconductor package. In the drawing, the reference number 10 is a semiconductor chip which is bonded to a chip pad 1 of a lead frame 20 using die bonding epoxy 2. A plurality of pads of the semiconductor chip 10 are electrically connected to a plurality of inner leads 3 of the lead frame 20 respectively by means of their associated metal wires 5, the opposed ends of which metal wires 5 are bonded to the pads of the chip 10 and to the inner leads 3 of the lead frame 20. After wire bonding for electrically connecting the chip 10 to the inner leads 3, a predetermined volume including the chip 10, the inner leads 3 and the metal wires 5 is hermetically packaged using an epoxy molding compound, thus to form a package body 6 of the package. The lead frame 20 also includes a plurality of outer leads 4, which leads 4 extend outward from the inner leads 3 to the outside of the package body 6 at opposed sides of the body 6. The outer leads 4 of the lead frame 20 extend to a predetermined length and are trimmed and formed into a predetermined bent configuration. That is, the outer leads 4 of the lead frame 20 are bent inward and downward.
The above semiconductor package is produced by the following process.
The package producing process is started at a die bonding step for bonding the semiconductor chip 10 to the top surface of the chip pad 1 of the lead frame 20 using the die bonding epoxy 2. The die bonding step is followed by a wire bonding step for electrically connecting the pads of the semiconductor chip 10 to the inner leads 3 of the lead frame 20 by means of the metal wires 5. After the wire bonding step, a molding step for hermetically molding, using the epoxy molding compound, the predetermined volume including the semiconductor chip 10, the inner leads 3 of the lead frame 20 and the metal wires 5 is carried out, thus to form the package body 6. The molding step is followed by a trimming step in which lead support dambars (not shown) are cut so as to divide the integrated packages into individual packages and forming step in which the outer leads 4 of the lead frame 20 are formed into the predetermined bent configuration.
In the above semiconductor package produced through the above process, the semiconductor chip is electrically connected to the inner leads of the lead frame by means of the plurality of the metal wires bonded to the semiconductor chip and to the inner leads through the wire bonding step. Therefore, it is difficult in the typical semiconductor package to achieve the recent trend of diminution and thinness of the package. Another problem of the above package is resided in that the metal wires cause parasitic inductance and resistance which deteriorate the electric performance of the package.